Collecting biologically-relevant information using an earpiece

ABSTRACT

Aspects of the present disclosure provide a method for obtaining biological information associated with a user, comprising receiving electrical signals via a first electrode on an ear tip of an earpiece inserted in an ear of the user, receiving electrical signals via a second electrode on an external portion of the earpiece, and deriving an electrocardiogram (ECG) based on the signals received via the first electrode and the second electrode. Aspects also provide a method for determining a pulse travel time (PTT) associated with a user, comprising obtaining a proximal signal using an earpiece inserted in of the user, obtaining a distal signal using the earpiece, and deriving the PTT based on the obtained proximal signal and the obtained distal signal.

BACKGROUND

Aspects of the present disclosure generally relate to using an earpiececonfigured to collect biologically-relevant information and methods forcollecting biologically-relevant information using, at least,information collected via a surface of the ear canal or the outer ear.

Monitoring biologically-relevant information helps to determine avariety of characteristics of an individual. As an example,physiological sensing, biochemical sensing, and motion sensing, eitheralone or in combination, are used to monitor an individual's health.Monitoring the individual's health helps in preventative care and withthe diagnosis and treatment of diseases.

As a growing segment of the population ages and as the number ofindividuals with chronic conditions increases, it is desirable tocontinuously improve the methods by which health-related parameters arecollected and processed. Several challenges exist in improving themethod and apparatuses used for collecting information using forhealth-monitoring. The method and apparatus for obtaining theinformation should be convenient, comfortable for the user, andaccurate. Furthermore, health related parameters should be collected ina continuous and nonintrusive manner.

SUMMARY

Certain aspects provide a method for obtaining biological informationassociated with a user. The method includes receiving electrical signalsvia a first electrode on an ear tip of an earpiece inserted in an ear ofthe user, receiving electrical signals via a second electrode on anexternal portion of the earpiece, and deriving an electrocardiogram(ECG) based on the electrical signals received via the first electrodeand the second electrode.

According to aspects, the method further comprises determining adifference in potential between the electrical signals received via thefirst electrode and the electrical signals received via the secondelectrode. The ECG is derived based on the determined difference inpotential. According to aspects, the method further comprisesdetermining a blood pressure associated with the user based on thederived ECG.

According to aspects, the electrical signals received via the firstelectrode are obtained from the ear of the user, and the electricalsignals received via the second electrode are obtained from anotherlocation of the user having a different potential than the ear.According to one example, the method includes contacting a finger of theleft hand of the user on the second electrode to obtain the electricalsignals via the second electrode.

As described herein, the ear tip comprises a flexible, umbrella shapedear tip.

Certain aspects provide a method for determining a pulse travel time(PTT) associated with a user. The method includes obtaining a proximalsignal using an earpiece inserted in an ear of the user, obtaining adistal signal using the earpiece, and deriving the PTT based on theobtained proximal signal and the obtained distal signal.

According to aspects, the proximal signal comprises an electrocardiogram(ECG) pulse signal, and the distal signal comprises one of aphonocardiogram (PCG) signal obtained via a microphone located on theearpiece or a photoplethysmogram (PPG) signal obtained via an opticalsensor on the earpiece.

According to aspects, the proximal signal comprises an electrocardiogram(ECG) pulse signal, and the distal signal comprises a ballistocardiogram(BCG) signal obtained via an accelerometer on the earpiece.

According to aspects, the proximal signal comprises a ballistocardiogram(BCG) signal obtained via an accelerometer on the earpiece, and thedistal signal comprises one of a phonocardiogram (PCG) signal obtainedvia a microphone located on the earpiece or a photoplethysmogram (PPG)signal obtained via an optical sensor on the earpiece.

According to aspects, deriving the PTT comprises computing a delaybetween the proximal and distal signals. According to one example, themethod further comprises determining a blood pressure of the user basedon the computed delay.

Certain aspects provide an earpiece comprising a flexible, conductiveear tip, configured to receive electrical signals from a user of theearpiece and a housing coupled with the conductive ear tip, wherein thehousing is configured to transfer the electrical signals from theconductive tip to external electronic hardware.

According to aspects, the conductive ear tip comprises at least one ofan ear tip coated with conductive coating or an ear tip fabricated withconductive rubber. According to aspects, the conductive ear tipcomprises two or more sections, each section having its own electricalcontact for collecting electrical signals from the user.

According to aspects, a biosensor placed on the earpiece, wherein thebiosensor is configured to monitor at least one of sweat composition ofpH associated with the user.

According to aspects, the conductive ear tip is configured to transfersignals from the biosensor to the housing.

According to aspects, the earpiece comprises a multi-conductiveelectrode for monitoring Galvanic Skin Response (GSR) of the user.

According to aspects, the electrical signals collected by the conductivetip are used to produce at least one of an electroencephalogram (EEG),electrocardiogram (ECG), electromyogram (EMG), or electrooculogram(EOG), associated with the user.

According to aspects, the conductive ear tip comprises an umbrellashaped ear tip and is configured to create a seal with an ear canal ofthe user.

According to aspects, the earpiece comprises a shaft region between theumbrella shaped tip and the housing, and an electrical wire fortransmitting the electrical signals from the shaft region to thehousing, the electrical wire having a first end and a second end,wherein the first end is coupled with the shaft region and the secondend is coupled with the housing.

According to aspects, the conductive ear tip comprises a first electrodeand a second electrode, the first electrode extending into an ear canalof the user and the second electrode located on a surface of the tipexternal to the ear canal when the tip is positioned in the ear canal,wherein the first electrode and second electrode comprise a sensor forcollecting biologically relevant information associated with the user.According to an example, the first electrode is coated with asilver-based conductive coating and comprises a negative electrode andthe second electrode comprises an isolated conductive coated section ofone of the tip or the housing. According to one example, the secondelectrode comprises a portion of the housing covered with copper foil.

According to aspects, the earpiece further comprises at least one of amicrophone, accelerometer, or optical sensor configured to collectbiologically relevant information associated with the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the anatomy of a human ear.

FIG. 2 illustrates an example body surface potential map.

FIG. 3 illustrates an example earpiece having a flexible, coated eartip.

FIG. 4 illustrates an example of an electrode on an outside surface ofthe earpiece.

FIG. 5 illustrates an example of the electronic hardware coupled to theear tip that processes the signals from the first and second electrodesof the earpiece.

FIG. 6 illustrates a microphone or accelerometer placed in the ear tipof an earpiece.

FIG. 7 illustrates an example of data used to obtain a PTT.

FIG. 8 illustrates an example earpiece including a coated, flexible,umbrella shaped ear tip and a tail portion.

FIG. 9 illustrates example earpieces, each having a flexible, umbrellashaped ear tip.

FIG. 10 illustrates example earpieces, each having a flexible, umbrellashaped ear tip.

FIG. 11 illustrates an example earpiece with damage on the flexible eartip.

FIG. 12 illustrates an example earpiece including peaks and valleys onthe umbrella shaped ear tip.

FIG. 13 illustrates an example earpiece having a protective coating on aportion of the umbrella shaped ear tip.

FIG. 14 illustrates an example cross-sectional representation of anearpiece.

FIG. 15 illustrates example operations which may be performed to collectbiologically-relevant information associated with a user.

FIG. 16 illustrates example operations for determining a PTT associatedwith a user.

DETAILED DESCRIPTION

Aspects of the present disclosure relate to using an earpiece as awearable health monitoring system. Accordingly, biologically-relevantinformation is collected via the earpiece inserted in an ear of a user.According to one example, an earpiece is used to measure at least one ofthe blood pressure, respiration rate, heart rate, or heart ratevariability of a user continuously and non-intrusively. As describedherein, the earpiece is used to collect one or more of a pulse traveltime (PTT), an electroencephalogram (EEG), electrocardiogram (ECG),electromyogram (EMG), electrooculogram (EOG), galvanic skin response(GSR), sweat composition, or pH associated with the user of theearpiece.

Several factors contribute to a desirable, continuous, wearable healthmonitoring system. A practical wearable system should not be clearlystigmatizing. Preferably, the health monitoring system is unobtrusiveand discrete so as to provide some privacy. The system should becomfortable to wear with minimum interference to the user's activities.A comfortable and non-intrusive system ensures that the recordings arecarried out when users are monitored in their natural environment, andtherefore enables the acquisition of more representative, useful, andrealistic data. The system should be embedded onto a device that ensuresthe electrodes and sensors are firmly held in position. Accordingly, theelectrodes or sensors are not easily damaged or dislodged from thesystem. The system should be user friendly. For example, users should beable to use the system absent assistance from a trained professional. Inthis manner, the health monitoring system reduces operational costs.Finally, a desirable system is realistic, evidenced by feasibility ofmanufacturing.

The in-ear health monitoring system described herein advantageouslyfulfills the factors described above. In-ear headphones, which includeone or two earpieces with removable and replaceable soft ear tips, arecommercially available and widely-used for both communication andentertainment purposes. As will be described in more detail below, anear tip may include a soft, flexible tip and a tail. Soft, flexible tipsenhance the acoustic experience of a user by providing acoustic sealingwith the ear and mechanical stability. The tips are umbrella shaped andmade of a flexible material to comfortably seal with the ear. Aspects ofthe present disclosure provide at least one electrode on an ear tip ofan earpiece used to receive electrical signals from a user. Theelectrical signals are used to collect biologically-relevantinformation.

FIG. 1 illustrates the anatomy 100 of a human ear. The external auditorycanal, or ear canal, 102 is a passageway that leads from the outside ofthe head to the ear drum 104. The ear drum 104, which separates theexternal ear from the middle ear, transmits sound from the air to themiddle ear. The sound then travels to the semicircular canals 106 andcochlea 108 in the inner ear. The internal carotid artery 110 is a majorartery supplying the brain. The internal jugular vein 112 drains bloodfrom the head, brain, face, and neck and conveys it toward the heart.

As will be described with reference to the figures, the earpiece usedfor collecting biologically-relevant information advantageously includesa flexible, ear tip which creates a gentle seal with the ear canal 102.The flexible ear tip has an umbrella shape which allows amass-producible earpiece capable of conforming to the interior shape andform of a wide range of individual ear canals. The ear tip also includesa tail portion, extending from the umbrella shaped tip. Examples of suchear tips used to collect biological information for health monitoringare illustrated in FIGS. 3, 4, 6, and 8-14.

Example Use of a Conductive Earpiece

The following paragraphs describe an example of using earpieces withelectrodes. According to one example, a conductive ear tip is used todetermine an ECG of a user.

FIG. 2 illustrates an example body surface potential map 200. Thepotential values illustrated in FIG. 2 are provided for illustrativepurposes only. More generally, potentials on the body vary from highlypositive 204 to highly negative 202.

An ECG signal can be measured using two locations on the body withsimilar potentials. Accordingly, an ECG signal can be measured based onsignals received from a left and right ear. However, it is desirable tomeasure an ECG signal using two anatomical locations having potentialsdifferent enough to allow obtaining a good signal to noise ratio.

According to one example, a finger on the left hand has a highlypositive potential, while both ears have highly negative potentials. Afinger on the right hand or any other anatomical area can be used tomeasure an ECG signal in combination with the ear, but the left handwill provide a better signal to noise ratio.

FIG. 3 illustrates an example earpiece 300 having a flexible, coated eartip 304. The ear tip provides enough surface area contact with the skinto provide a usable signal for determining an ECG. The soft, flexiblematerial of the tip helps the tip to conform to the ear geometry andincreases the surface area having contact with a user's skin.Additionally, the flare of the umbrella shaped tip provides somespringiness so that some pressure is exerted by the tip on the skin.This pressure helps to lower the contact resistance between the coatingof the ear tip and the ear tip itself.

A first, negative, electrode is formed by the ear tip 304, coated withconductive material or fabricated with conductive material, inserted inthe ear canal. According to one example, a wire 302 running through theearpiece conveys the signal to external, electronic hardware. Accordingto another example, the signal is wirelessly conveyed to externalelectronic hardware.

FIG. 4 illustrates an example 400 of an electrode on an outside surfaceof the earpiece. In one example, a second electrode may be anyelectrically isolated and conductive region on the ear tip, tail or thehousing. An electrode on the outside surface of the earpiece is anelectrically isolated conductive region formed by coating the ear tip orusing conductive rubber to fabricate the ear tip. According to oneexample, the electrode on the outer part of the earpiece is covered withcopper foil. The copper foil forms a second, positive electrode.

After the ear tip 402 is placed in the ear, at, 404, the user contactsthe isolated conductive region with a finger of the left hand. Accordingto this example, the combination of the first and second electrodes formthe ECG sensor—the left hand and either ear being at potential ofopposite signs. In other examples, the combination of the first andsecond electrodes may form an electrical sensor for determining an EEC,EMG, or EOG.

FIG. 5 illustrates an example 500 of the electronic hardware coupled tothe ear tip that processes the signals from the first and secondelectrodes of the earpiece.

The first electrode 502 and the second electrode 504 are coupled toinput buffers 506 and 508, respectively.

The input buffers 506 and 508 are high impedance amplifiers. The inputbuffers match the high impedance of the electrodes 502 and 504 to therelatively low impedance of connecting cables or wires. The inputbuffers are placed as close as possible to the electrodes to minimizethe length of high impedance connections, thereby minimizing effects ofexternal electric field interference.

Signals from input buffers 506 and 508 are connected to inputs of adifferential amplifier 510. The differential amplifier 510 amplifies thedifference between the electrode signals and suppresses unwanted commonmode interference signals.

50/60 Hz AC power lines can cause harmful, strong interference to ECGmeasurement. Accordingly, a rejection filter 512 tuned to the AC linemain frequency removes the 50/60 Hz signal from the output ofdifferential amplifier 1310.

A higher-order low pass filter 514 suppresses harmonics of 50/60 Hz ACpower line interference before the electrical signal is fed to a dataacquisition system. The arrangement of the filters 512 and 514 is neededfor an efficient utilization of dynamic range and resolution of dataacquisition system. As a general matter, all the elements of FIG. 5 maybe included in a single integrated circuit, or in discrete components.

Example Derivation of Pulse Travel Time

One technique for determining blood pressure uses the pulse travel time(PTT), generally the time it takes each pulse to travel from the heartto the point at which it is measured. PTT is derived using two signalsbetween which a delay exists. One sensor is used to measure a proximalsignal and another sensor is used to measure a distal signal. The delaybetween the proximal signal and the distal signal is inverselycorrelated to a user's blood pressure. The greater the delay between thetwo signals, the higher the blood pressure prediction accuracy.

The order of arrival of the signals at the sensor location is: (1)electrocardiogram (ECG) pulse signal, (2) ballistocardiogram (BCG)signal, and (3) photoplethysmogram (PPG) or in-ear phonocardiogram (PCG)pulse signal. ECG and BCG represent the heartbeat, and can be detectedat the same site as the pulse, as the delay due to the speed of electricor acoustic waves through the body is much less than the delay of thepulse wave through the blood, which is detected by the PPG or PCG. TheBCG signal may be obtained using an accelerometer placed on the ear tip.The PPG signal may be obtained using an optical sensor on the ear tip.The PCG signal may be obtained using a microphone on the ear tip. Theaccelerometer and microphone do not need to contact the skin;accordingly, they may be placed anywhere on the ear tip with sufficientacoustic coupling to the body to detect the signals.

According to one example, the ECG pulse signal is the proximal signaland a PPG or an in-ear phonocardiogram PCG pulse signal is the distalsignal.

Advantageously, this combination of proximal and distal signals providesa large delay. In particular, the delay between ECG and the pulse signalis, within sensing tolerances, equivalent to the PTT. According toanother example, an accelerometer providing a ballistocardiogram (BCG)signal is used to compute a PTT. The BCG signal is the proximal signaland the PPG or PCG pulse signal is the distal signal. According toanother example, the accelerometer signal is the distal signal and theECG pulse signal is the proximal signal.

FIG. 6 illustrates a microphone or accelerometer placed in the ear tipof an earpiece 600. According to an example, a microphone, such as aMicroElectrical-Mechanical System (MEMS) microphone, placed in the eartip is used to obtain an in-ear PCG signal. As illustrated in FIG. 1,the internal carotid artery 110 runs close to the ear canal 102 and islikely to be the cause of a received acoustic signal. Additionally oralternatively, an accelerometer is placed in the ear tip. The microphoneand accelerometer may be placed anywhere on the earpiece 600 that it isacoustically coupled to the user's body, because they do not need tocontact the skin. For example, a microphone coupled to the air insidethe ear canal can detect the sound of the pulse without directlycontacting the body. According to an example, the accelerometer isattached to the housing and is therefore mechanically coupled to theuser.

FIG. 7 illustrates an example of the data 700 used to obtain a PTT. Thederived PTT may be used to determine a user's blood pressure. First,signal are obtained from different sensors, such as an ECG sensor,microphone, accelerometer, or optical, PPG sensor. The signal curves foran ECG signal, signal derived from an accelerometer, and signal derivedfrom a microphone are illustrated in FIG. 7.

While not illustrated, the obtained signals are filtered, in an effortto enhance the signals. The signal can be filtered using frequency-basedfiltering, time averaging, and/or removing uncorrelated noise present inone signal but not the others. To remove uncorrelated noise, each sensoris used to enhance the signal obtained from other sensors.

After the signals are filtered, possibly relevant parameters from signalcurves are extracted. One specific and important parameter is the PTT,which is the time delay between the different signals. The time delaycan be computed in multiple ways such as peak-to-peak, trough-to-trough,or cross-correlations. According to aspects, the delay is calculatedusing a variety of methods and each of the derived quantities provides adifferent parameter. Other example parameters include the peakmagnitudes, widths, and slope values.

Each of the collected parameters is correlated with diastolic orsystolic blood pressure, for example, by computing Spearman's orPearson's correlation coefficients. Correlated, relevant parameters areused to find the coefficients for a linear regression or polynomialregression, a logarithmic fit, or any machine learning technique thatwill predict blood pressure from the measurement of those parameters.

The pulse wave velocity is correlated to blood pressure. PTT isinversely proportional to pulse wave velocity, wherein themultiplicative factor is the distance between the two locations—aproximal location and a distal location. Therefore, PTT is correlated toblood pressure and can be used to predict blood pressure. Morespecifically, PTT is used to determine a change in a user's bloodpressure. See, for example, Mukkamala, Ramakrishna, et al. “TowardUbiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory andPractice.” IEEE Transactions on Biomedical Engineering 62.8 (2015):1879-1901, for additional, publically-available information.

FIG. 7 illustrates an example plot of voltage versus time of the ECGsignal, PCG signal, and accelerometer signal. Reference points areselected for each of the three signals to determine their time ofoccurrence. For example, a peak time or a trough time is selected foreach of the ECG signal, the PCG signal, and the accelerometer signal.

According to an example, a delay between the signals is determined. Forexample, a peak of the ECG signal, a peak of the PCG signal, and a peakof the accelerometer signal are calculated. The delay is computed bycross-correlation, replica correlation, or various methods of signalaveraging, such as using the ECG signal as a trigger to average the PCGsignal. Relevant parameters are filtered and averaged over a few beats.

According to aspects, trough-to-trough delay, a maximum slope delay, apeak-to-peak delay, a peak value, a foot value, second peak value, or apulse width are extracted from the ECG, PCG, and accelerometer signalsin an effort to determine a user's blood pressure.

Multiple sensors are used to enhance the signals collected by each ofthe sensors. The multiple sensors are used to remove uncorrelated noiseand the increase signal to noise ratio of collected signals. Use of thesame sensors, such as an accelerometer, microphone, or optical sensor,on ear tips in both ears, will help improve the signal to noise ratioand remove uncorrelated noise.

Other biologically relevant information can be collected using the eartip described herein. Heart rate, heart rate variability, and arespiratory rate can be determined using sensors on the ear tip. Theheart rate is obtained by counting the number of peaks in a signal overa period of time, such as a minute, or by looking at the delay betweentwo consecutive peaks of a same signal. The delay between twoconsecutive peaks may be referred to as an RR interval. Heart ratevariability corresponds to statistics, such as a standard deviation,associated with the variations of the heart rate beat-to-beat.Accordingly, it is derived from delays between two consecutive peaks. Arespiratory rate is derived from the beat-to-beat heart rate as aperiodic oscillation of the heart rate over time. It is also derivedfrom the beat-to-beat PTT as a periodic (almost sinusoidal) oscillationof this PTT over time.

Conductive Earpiece

FIG. 8 illustrates an example earpiece 800 including a coated, flexible,umbrella shaped ear tip and a tail portion. As illustrated in FIG. 8,the umbrella shaped ear tip is divided in two sections 804 a and 804 b.The tail is illustrated at 802. The housing 806 includes electronichardware and a driver. According to one example, the housing is internalto the earpiece 800. For the earpiece to function as health monitoringsystem, the ear tip surface in contact with the skin of a user isconductive.

According to one example, the ear tip is coated with a conductivecoating 804. The conductive coating can be continuous (not illustratedin FIG. 8) or can have more than one section. Each section 804 a, 804 bof the coating acts as a separate electrode used to collect biologicalinformation associated with a user. While two conductive coatingsections are illustrated in FIG. 8, the earpiece 800 can have anyinteger number of conductive coatings. Having multiple electrodes isuseful to compute GSR, EEG, EOG, EMG, or ECG as differences ofpotential. Additionally, having several sections wherein each sectionacts as a separate electrode improves the signal to noise ratio byremoving uncorrelated noise.

According to an aspect, the conductive coating functions as an electrodeto collect biological information associated with the user. The coatingmaterial may be one of Ag, AgCl/Ag, conductive carbon, graphene, orother biocompatible conductive material. The ear tip coated with one ofthese conductive coatings is used to collect information related to EEG,ECG, EOG, EMG, or GSR by contacting the skin of a user. In one example,the umbrella shaped ear tip of the earpiece contacts an interior portionof an ear canal. According to another example, the entire earpiece,including the umbrella shaped ear tip and tail, are coated with aconductive coating. The conductive coating can be continuous or can havemore than one section.

FIG. 9 illustrates example earpieces 900, each having a flexible,umbrella shaped ear tip. As illustrated at 902, the entire earpiece isfabricated with silicone. As illustrated at 904, the umbrella-shaped eartip 906 is fabricated with conductive rubber and the tail is fabricatedwith silicone. According to aspects, the conductive rubber used tofabricate the ear tip is made of a metal-filled substance such assilicone, polyurethane, or thermal plastic rubber. Using injectionmolding tools in the fabrication process of the ear tip 904, theconductive portions of the ear tip 906 can be electrically divided intoseveral sections, wherein each section functions as an electrode. Aconductive coating, as described with reference to FIG. 8, may befurther added on top of the conductive rubber electrodes illustrated inFIG. 9.

FIG. 10 illustrates example earpieces 1000 each having a flexible,umbrella shaped ear tip. As illustrated at 1002, the earpiece isfabricated with regular rubber. The earpiece 1004 is entirely coveredwith a conductive rubber. According to aspects, the conductive rubberused to fabricate the earpiece 1004 is texturized before coating. Usinginjection molding tools in the fabrication process of the earpiece 1004,the conductive portions of the earpiece can be electrically divided intoseveral sections, wherein each section functions as an electrode.

As described above, the earpiece is made conductive by applying acoating (shown in FIG. 8) or by fabricating the earpiece or ear tip witha conductive material (shown in FIGS. 9 and 10). According to aspects,other biosensors are added to the earpiece. According to aspects, one ormore optical sensors, microphones, or accelerometers are placed in theear tip or in the housing internal to the earpiece. According to anotherexample, biosensors monitor sweat composition, pH, etc. Sweat isproduced and collected between skin and the ear tip. Accordingly, theear tip is an advantageous location to collect enough sweat to determineproperties of a user's sweat. Signals from the biosensors aretransferred through the conductive coating for processing to extractbiologically relevant information.

FIG. 11 illustrates an example earpiece 1100 with damage on the flexibleear tip. For illustrative purposes, the ear tip is coated with aconductive coating 1104 as described with reference to FIG. 8; however,the earpiece or the ear tip 1100 could be fabricated with conductiverubber as shown in FIGS. 9 and 10. An electrode on the umbrella portionof the ear tip may crack or be damaged by handling. For example, a userapplies pressure on the ear tip to place it in the ear canal.Specifically, the sensitive region 1102 of the ear tip gets damaged whenthe tip rubs the inner surface of the ear canal or becomes distortedduring handling or insertion in the ear.

FIG. 12 illustrates an example earpiece 1200 including peaks and valleyson the umbrella shaped ear tip. Earpiece 1208 is a cross-sectional viewof the earpiece 1202. The peaks 1204 and valleys 1206 on the umbrellashaped ear tip mitigate damage to the sensitive region of the ear tip.Only peaks 1204 will be rubbed off through handling of the ear tip. Thevalleys 1206 will provide electrical conductivity.

FIG. 13 illustrates an example earpiece 1300 having a protective coatingon a portion of the umbrella shaped ear tip. 1302 and 1306 illustratethe same earpiece from different perspectives. A protective coating 1304is applied on the sensitive region of the umbrella shaped ear tip toreduce damage to the ear tip and maintain conductivity.

FIG. 14 illustrates an example cross-sectional representation of anearpiece 1400, including an umbrella shaped ear tip, shaft region, andconductive material. 1402 and 1408 illustrate the same earpiece fromdifferent perspectives. The earpiece includes a shaft region 1404between the ear tip 1410 and the housing 1412. An electrical signalmoves from the exterior of the ear tip 1410 to the shaft region 1404.The signal is then transmitted to the plastic housing 1412 that holdselectronics. To facilitate this transfer, the plastic housing has metalcoextruded 1406 to provide a contact area to receive the signal from thecoating in the shaft region 1404. This electrical connection method isalso applicable if the ear tip is made from a conductive rubber as shownin FIG. 10. In another aspect, the plastic housing can remaininsulating, and an electrical wire is attached to the shaft region 1404and is connected to the electronics inside the plastic housing 1412.

As described above, a flexible, conductive ear tip contacts a surface ofthe ear of a user. The ear tip is configured to receive electricalsignals from the user of the earpiece. The housing coupled with the eartip is configured to transfer the electrical signals to electronichardware for processing.

FIG. 15 illustrates example operations 1500 which may be performed tocollect biologically-relevant information associated with a user, inaccordance with aspects of the present disclosure. At 1502, theelectrical signals are received via a first electrode on an ear tip ofan earpiece inserted in an ear of the user. At 1504, electrical signalsare received via a second electrode on an external portion of theearpiece. At 1506, an ECG is derived based on the electrical signalsreceived via the first electrode and the second electrode.

FIG. 16 illustrates example operations 1600 for determining a PTTassociated with a user. At 1602, a proximal signal is obtained using anearpiece inserted in an ear of the user. At 1604, a distal signal isobtained using the earpiece. At 1606, the PTT is derived based on theobtained proximal signal and the obtained distal signal.

The operations 1500 and 1600 may be performed using an earpiece asdescribed herein and illustrated in the figures. Accordingly, electrodeson an earpiece are used to measure an ECG at an ear. A PTT is derivedusing the earpiece.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for obtaining biological informationassociated with a user, comprising: receiving electrical signals via afirst electrode on an ear tip of an earpiece inserted in an ear of theuser; receiving electrical signals via a second electrode on an externalportion of the earpiece; and deriving an electrocardiogram (ECG) basedon the electrical signals received via the first electrode and thesecond electrode.
 2. The method of claim 1, further comprising:determining a difference in potential between the electrical signalsreceive via the first electrode and the electrical signals received viathe second electrode, and wherein the ECG is derived based on thedetermined difference in potential.
 3. The method of claim 1, furthercomprising: determining a blood pressure associated with the user basedon the derived ECG.
 4. The method of claim 1, wherein the electricalsignals received via the first electrode are obtained from the ear ofthe user, and wherein the electrical signals received via the secondelectrode are obtained from another location of the user having adifferent potential than the ear.
 5. The method of claim 4, furthercomprising: contacting a finger of the left hand of the user on thesecond electrode to obtain the electrical signals via the secondelectrode.
 6. The method of claim 1, wherein the ear tip comprisesflexible, umbrella shaped ear tip.
 7. A method for determining a pulsetravel time (PTT) associated with a user, comprising: obtaining aproximal signal using an earpiece inserted in an ear of the user;obtaining a distal signal using the earpiece; and deriving the PTT basedon the obtained proximal signal and the obtained distal signal.
 8. Themethod of claim 7, wherein the proximal signal comprises anelectrocardiogram (ECG) pulse signal, and wherein the distal signalcomprises one of a phonocardiogram (PCG) signal obtained via amicrophone located on the earpiece or a photoplethysmogram (PPG) signalobtained via an optical sensor on the earpiece.
 9. The method of claim7, wherein the proximal signal comprises an electrocardiogram (ECG)pulse signal, and wherein the distal signal comprises aballistocardiogram (BCG) signal obtained via an accelerometer on theearpiece.
 10. The method of claim 7, wherein the proximal signalcomprises a ballistocardiogram (BCG) signal obtained via anaccelerometer on the earpiece, and wherein the distal signal comprisesone of a phonocardiogram (PCG) signal obtained via a microphone locatedon the earpiece or a photoplethysmogram (PPG) signal obtained via anoptical sensor on the earpiece.
 11. The method of claim 7, whereinderiving the PTT comprises: computing a delay between the proximal anddistal signals.
 12. The method of claim 11, further comprising:determining a blood pressure of the user based on the computed delay.13. An earpiece comprising: a flexible, conductive ear tip, configuredto receive electrical signals from a user of the earpiece; and a housingcoupled with the conductive ear tip, wherein the housing is configuredto transfer the electrical signals from the conductive tip to externalelectronic hardware.
 14. The earpiece of claim 13, wherein theconductive ear tip comprises at least one of an ear tip coated withconductive coating or an ear tip fabricated with conductive rubber. 15.The earpiece of claim 13, wherein the conductive ear tip comprises twoor more sections, each section having its own electrical contact forcollecting electrical signals from the user.
 16. The earpiece of claim13, further comprising: a biosensor placed on the earpiece, wherein thebiosensor is configured to monitor at least one of sweat composition ofpH associated with the user.
 17. The earpiece of claim 16, wherein theconductive ear tip is configured to transfer signals from the biosensorto the housing.
 18. The earpiece of claim 13, further comprising: amulti-conductive electrode for monitoring GS Skin Response (GSR) of theuser.
 19. The earpiece of claim 13, wherein the electrical signalscollected by the conductive tip are used to produce at least one of anelectroencephalogram (EEG), electrocardiogram (ECG), electromyogram(EMG), or electrooculogram (EOG), associated with the user.
 20. Theearpiece of claim 13, wherein the conductive ear tip comprises anumbrella shaped ear tip and is configured to create a seal with an earcanal of the user.
 21. The earpiece of claim 20, further comprising: ashaft region between the umbrella shaped tip and the housing; and anelectrical wire for transmitting the electrical signals from the shaftregion to the housing, the electrical wire having a first end and asecond end, wherein the first end is coupled with the shaft region andthe second end is coupled with the housing.
 22. The earpiece of claim13, wherein the conductive ear tip comprises a first electrode and asecond electrode, the first electrode extending into an ear canal of theuser and the second electrode located on a surface of the tip externalto the ear canal when the tip is positioned in the ear canal, whereinthe first electrode and second electrode comprise a sensor forcollecting biologically relevant information associated with the user.23. The earpiece of claim 22, wherein the first electrode is coated witha silver-based conductive coating and comprises a negative electrode andthe second electrode comprises an isolated conductive coated section ofone of the tip or the housing.
 24. The earpiece of claim 22, wherein thesecond electrode comprises: a portion of the housing covered with copperfoil
 25. The earpiece of claim 13, further comprising: at least one of amicrophone, accelerometer, or optical sensor placed on the earpiececonfigured to collect biologically relevant information associated withthe user.